SYNTHESIS AND CHARACTERIZATION OF ION SEPARATED MU2(OBU(T))9 SPECIES WHERE M=NBU(N)(4), PPH4, PH3PME AND K-DIBENZO-18-CROWN-6

Reaction of the molecular species KU2(OBu(t))9 with bromide salts of n on-coordinating counter-cations, MBr (M = NBu(n)4, PPh4 and Ph3PMe) in THF solution results in the precipitation of KBr and the formation of the ion separated MU2(OBu(t))9 salts. The potassium cation can also b e removed from the coordination sphere of the dinuclear uranium anion by reaction with dibenzo-18-crown-6 ether in THF. These compounds have been characterized by H-1 NMR and electronic absorption spectroscopy. H-1 NMR indicates that the dinuclear face-shared bioctahedral structu re of the U2(OBu(t))9 anion is retained in the ion separated species. Comparison of the electronic absorption spectra of KU2(OBu(t))9 with t he dinuclear U2(OBu(t))9 anion in solution also supports this conclusi on.